Cowl structure of vehicle

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2005-103847 filed on Mar. 31, 2005 the entire contents of which are hereby incorporated by reference.

1. Field of the Invention

The present invention relates to a cowl structure of a vehicle for covering an outside of a vehicle body and an engine.

2. Description of Background Art

A cowl structure is known wherein an aerodynamic characteristic of a vehicle is enhanced by the cowl structure of the vehicle. Such a cowl structure includes upper and lower air guide fins which extend longitudinally and range from a rear portion of a front wheel to a front portion of a rear wheel. The upper and lower air guide fins are mounted on sides of a cowling. In such a cowl structure of the vehicle, when the vehicle is largely banked at the time of turning, one side wall of a V-shaped portion of an air guide fin which is formed on a lower portion of the cowling approaches a road surface thus generating a Venturi effect. Air traveling past the cowling at a high speed due to the Venturi effect generates a negative pressure. The negative pressure acts on the cowling as a downward force so as to increase a gripping force of the front and rear wheels to the road surface. See, for example, JP-A-8-225092.

However, in JP-A-8-225092, since the air guide fins extend to range from the rear portion of the front wheel to the front portion of the rear wheel in the longitudinal direction of the cowling, a length of the air guide fins in the longitudinal direction is elongated. Thus, it is possible that a weight of the vehicle is increased. Further, the appearance of the vehicle is not favorable.

SUMMARY AND OBJECTS OF THE INVENTION

It is an object of an embodiment of the present invention to overcome the above-mentioned drawbacks and to provide a cowl structure of a vehicle for improving the appearance of a vehicle without increasing the weight of the vehicle and also for enhancing the aerodynamic characteristic of the vehicle.

To achieve the above-mentioned object, an embodiment of the present invention is directed to a cowl structure of a vehicle which includes a front cowl for covering a front portion of a vehicle body with a radiator being positioned in front of cylinder heads of an engine. A radiator cover is provided for covering the radiator. The radiator cover ranges from side surfaces to a lower end of the radiator with bulging portions that bulge from a front portion to a rear portion of the radiator cover. The bulging portions are formed in the rearward and upward oblique direction in a side view of the vehicle and are formed on a lower end portion of the radiator cover.

According to an embodiment of the present invention, the front cowl includes projecting portions which bulge toward an outside of the vehicle body as compared to the bulging portions behind the radiator.

According to an embodiment of the present invention, the projecting portions are positioned above the bulging portions.

According to an embodiment of the present invention, the radiator cover includes an opening portion which opens toward a rear portion of the vehicle body.

According to the cowl structure of an embodiment of the invention, the bulging portions which are formed in the rearward and upward oblique direction as viewed in a side view of the vehicle are, in the vicinity of a head pipe and a front fork, mounted on the lower end portion of the radiator cover which covers the radiator ranging from side surfaces to a lower end of the radiator in front of cylinder heads of the engine. Thus, it is possible to easily apply the downward force (downward thrust) which pushes a vehicle body downwardly to a front wheel. Further, the bulging portions which apply the downward force to the front wheel are mounted on the lower end portion of the radiator cover. Thus, different from the conventional structure, there exists no possibility that a length of the cowl structure in the longitudinal direction is elongated. According to an embodiment of the present invention, it is unnecessary to increase the weight of the vehicle body and it is also possible to improve the appearance of the vehicle.

According to the cowl structure of an embodiment of the present invention, the projecting portions of the front cowl bulge toward the outside of the vehicle body as compared to the bulging portions behind the radiator. Thus, it is possible to enhance an aerodynamic characteristic of the vehicle by smoothly making use of a air that travels over the cowling and is deflected toward the outside of the vehicle body by the bulging portions and is directed toward a rear portion of the vehicle body.

According to the cowl structure of an embodiment of the present invention, the projecting portions formed on the front cowl are arranged above the bulging portions. Thus, portions of the air that travels over the cowling are deflected toward the upper portion of the vehicle body by the bulging portions and are received by the lower surfaces of the projecting portions so as to change the directions of the flow of the portions of the traveling air downwardly. Thus, it is possible to reduce an influence of the air on a rider.

According to the cowl structure of an embodiment of the invention, since the radiator cover forms the opening portion which opens toward the rear portion of the vehicle body, a negative pressure is generated behind the radiator cover by the air that travels thereover and is deflected as the traveling air passes the bulging portions of the radiator cover during operation of the vehicle. Accordingly, the air can easily pass trough the radiator. Thus, it is possible to enhance a cooling efficiency of the radiator.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

<figref idref="DRAWINGS">FIG. 1</figref> illustrates a perspective view as viewed from an oblique front direction of a motorcycle which mounts the cowl structure of a vehicle according to the present invention thereon;

<figref idref="DRAWINGS">FIG. 2</figref> illustrates a side view of the motorcycle shown in <figref idref="DRAWINGS">FIG. 1</figref>;

<figref idref="DRAWINGS">FIG. 3</figref> illustrates a plan view of the motorcycle shown in <figref idref="DRAWINGS">FIG. 1</figref>;

<figref idref="DRAWINGS">FIG. 4</figref> illustrates an enlarged view of the surrounding of a radiator of the motorcycle shown in <figref idref="DRAWINGS">FIG. 2</figref>;

<figref idref="DRAWINGS">FIG. 5</figref> illustrates a perspective view of the motorcycle shown in <figref idref="DRAWINGS">FIG. 1</figref> as viewed from the oblique front direction for explaining the mounting relationship among respective parts around the radiator;

<figref idref="DRAWINGS">FIG. 6</figref> illustrates a single-body side view of a left outer cowl used in a motorcycle shown in <figref idref="DRAWINGS">FIG. 1</figref>; and

<figref idref="DRAWINGS">FIG. 7</figref> illustrates a single-body side view of a left inner cowl used in a motorcycle shown in <figref idref="DRAWINGS">FIG. 1</figref>.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, best modes for carrying out of a cowl structure of a vehicle according to the present invention are explained in detail in conjunction with the drawings.

<figref idref="DRAWINGS">FIG. 1</figref> to <figref idref="DRAWINGS">FIG. 7</figref> show the first embodiment of the present invention. As shown in <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, the motorcycle <b>10</b> is a vehicle that includes a frame <b>11</b>, a front fork <b>13</b> which is mounted on a head pipe <b>12</b> provided to a front portion of the frame <b>11</b> and a handle <b>14</b> which is connected to an upper portion of the front fork <b>13</b>. A front wheel <b>15</b> is mounted on a lower portion of the front fork <b>13</b>. A power unit <b>16</b>, which includes an engine <b>17</b> and a transmission <b>18</b>, is mounted on a front lower portion of the frame <b>11</b>. A swing arm <b>19</b> is mounted on a rear lower portion of the frame <b>11</b> with a rear wheel <b>20</b> being mounted on the swing arm <b>19</b>. A tandem seat <b>22</b> is mounted on a rear upper portion of the frame <b>11</b> by way of seat rails <b>21</b>. The rear wheel <b>20</b> is driven by the power unit <b>16</b>.

Further, the motorcycle <b>10</b> includes a radiator <b>23</b> which is arranged below a front portion of the frame <b>11</b>. The motorcycle <b>10</b> also includes a front cowl <b>50</b> for covering a front portion and both front side portions of the frame <b>11</b> with a rear cowl <b>60</b> for covering a rear portion and both rear side portions of the frame <b>11</b>. An inner cowl <b>70</b> is provided which integrally incorporates a radiator cover <b>71</b> surrounding the radiator <b>23</b> therein. The inner cowl <b>70</b> is mounted in the inside of the front cowl <b>50</b>. The front cowl <b>50</b>, the rear cowl <b>60</b> and the inner cowl <b>70</b> are formed by molding using a synthetic resin such as a lightweight FRP.

The frame <b>11</b> includes a pair of left and right main frames <b>24</b> which are formed into a substantially U-shape by casting an aluminum alloy, for example. The left and right main frames <b>24</b> extend rearwardly and downwardly. A cylindrical head pipe <b>12</b> is mounted on a front end portion of the main frames <b>24</b>. In addition, the frame <b>11</b> also includes a down tube <b>25</b> which is connected to the front end portion of the main frame <b>24</b> and extends in the rearward and downward direction to a rear portion of the head pipe <b>12</b>. A front bracket <b>26</b> is provided which extends to a front portion of the head pipe <b>12</b> in a state wherein the front bracket <b>26</b> extends upwardly in a substantially L-shape. A pivot plate <b>27</b> is arranged at a lower rear end portion of the main frame <b>24</b> which is connected to a front end portion of the seat rail <b>21</b> which extends in the rearward and upward direction.

In the power unit <b>16</b>, the engine <b>17</b> is a water-cooled 4-stroke OHC system 3-valve V-type two-cylinder engine which integrally incorporates the transmission <b>18</b> therein. The engine <b>17</b> is supported on the main frame <b>24</b>, the pivot plate <b>27</b> and the down tube <b>25</b>. Above the power unit <b>16</b>, a fuel tank <b>28</b> is mounted on an air cleaner (not shown in the drawings). In the engine <b>17</b>, a carburetor (not shown in the drawings) is connected to intake ports of a front cylinder-side cylinder head <b>17</b><i>a </i>and a rear cylinder-side cylinder head <b>17</b><i>b</i>, while an exhaust pipe <b>29</b> of the front cylinder-side cylinder head <b>17</b><i>a </i>and an exhaust pipe <b>30</b> of the rear cylinder-side cylinder head <b>17</b><i>b </i>are connected to a collecting pipe <b>31</b> below the engine <b>17</b>. The collecting pipe <b>31</b> is connected to a muffler <b>32</b>. An output of the transmission <b>18</b> is taken out from a side portion of the transmission <b>18</b> and is transmitted to a sprocket wheel (not shown in the drawings) which is fixed to the rear wheel <b>20</b> by way of a chain (not shown in the drawings).

A front suspension (not shown in the drawings), which includes a coil spring and a damper, is incorporated in the front fork <b>13</b>. At the same time, a caliper <b>34</b> which imparts a braking force to a pair of disk rotors <b>33</b> fixed to the front wheel <b>15</b> is assembled to the front fork <b>13</b>. A front fender <b>35</b> for covering an upper portion of the front wheel <b>15</b> is mounted on the front fork <b>13</b>.

The swing arm <b>19</b> is tiltably supported on a pivot plate <b>27</b> and is dampened by a rear suspension (not shown in the drawings) which includes a coil spring and a damper which is arranged between the swing arm <b>19</b> and the frame <b>11</b>. Further, a disk rotor <b>35</b> is mounted on the rear wheel <b>20</b> in the same manner as the front wheel <b>15</b>.

The radiator <b>23</b> is fixed to the down tube <b>25</b> using bolts behind the front wheel <b>15</b> and in front of a front-cylinder-side cylinder head <b>17</b><i>a </i>of the engine <b>17</b>. Further, a periphery of a side portion of the radiator <b>23</b> is covered with a radiator cover <b>71</b> which is formed below an inner cowl <b>70</b>.

The front cowl <b>50</b> includes a front center cowl <b>51</b>, left and right outer cowls <b>52</b>, <b>52</b>, and left and right middle cowls <b>53</b>, <b>53</b>.

The front center cowl <b>51</b> mounts a head light unit <b>37</b> on a distal end of a front surface thereof and mounts a center air inlet <b>51</b><i>a </i>on a portion thereof below the head light unit <b>37</b>. Further, a pair of left and right side air inlets <b>51</b><i>b</i>, <b>51</b><i>b </i>is mounted on both sides of the center air inlet <b>51</b><i>a </i>in a symmetric manner on the left-and-right.

The front center cowl <b>51</b> is arranged between front distal ends of the left and right outer cowls <b>52</b>, <b>52</b> and is fixed to a front bracket <b>26</b> using bolts. The center air inlet <b>51</b><i>a </i>is arranged at the center of a front end portion of the front center cowl <b>51</b> and above the front wheel <b>15</b>. Thus, air is introduced from a front side and is supplied to an air cleaner during operation of the vehicle. Since side air inlets <b>51</b><i>b</i>, <b>51</b><i>b </i>are arranged on both sides of a front end portion of the front center cowl <b>51</b> and above the front wheel <b>15</b>, portions of the air that is introduced are made to flow in the direction toward the left and right middle cowls <b>53</b>, <b>53</b> during operation of the vehicle.

A wind screen <b>38</b> is fixed to an upper portion of the front center cowl <b>51</b>. A meter unit (not shown in the drawing) is fixed to the front bracket <b>26</b> and is arranged in the inside of the front center cowl <b>51</b>. By combining the front center cowl <b>51</b> with the left and right outer cowls <b>52</b>, <b>52</b>, the front center cowl <b>51</b> receives the air during the operation of the vehicle from the front side to thus impart a downward force to the front wheel <b>15</b>.

Since the left and right outer cowls are formed to be symmetric in a left-and-right direction, only the left outer cowl <b>52</b> is explained here. The outer cowl <b>52</b> is arranged in a state wherein the outer cowl <b>52</b> covers a side portion of the head pipe <b>12</b>, a front side portion of the main frame <b>24</b>, and side portions of both cylinder heads <b>17</b><i>a</i>, <b>17</b><i>b </i>of the engine <b>17</b>. The outer cowl <b>52</b> is fixed to the main frame <b>24</b>, the pivot plate <b>27</b> and the front bracket <b>26</b> using bolts.

The outer cowl <b>52</b> includes a side-winker notch <b>52</b><i>b </i>which is arranged on an upper portion of the outer cowl <b>52</b>, a middle-cowl notch <b>52</b><i>c</i>, and a projecting portion <b>52</b><i>d </i>which is arranged below the middle cowl <b>53</b>.

To the side-winker notch <b>52</b><i>b</i>, the side-winker <b>39</b> which is connected to the front bracket <b>26</b> by using a bolt.

On the middle-cowl notch <b>52</b><i>c</i>, a middle cowl <b>53</b> which is connected to the main frame <b>24</b> is mounted by using a bolt. The middle cowl <b>53</b> includes a slit-shaped opening (not shown in the drawings) which is directed to the side air inlet <b>51</b><i>b </i>of the front center cowl <b>51</b>. Thus, it is possible to allow the air during operation to be introduced from both side air inlets <b>51</b><i>b</i>, <b>51</b><i>b </i>to flow rearwardly along the side surfaces of the vehicle body.

Further, the projecting portion <b>52</b><i>d </i>is formed in an inverse-triangular-shape as viewed from the vehicle body side surface direction and is formed in a wing shape extending from a front portion to a rear portion and, thereafter, bulges toward the outside of the vehicle body at a rear-side position of the radiator <b>23</b>. In the projecting portion <b>52</b><i>d</i>, an upper surface <b>52</b><i>e </i>which forms an upper portion of the projecting portion <b>52</b><i>d </i>is arranged substantially horizontally, a lower surface <b>52</b><i>f </i>which forms a front lower portion of the projecting portion <b>52</b><i>d </i>is arranged in the rearward and downward direction, and an air outlet <b>52</b><i>g </i>is formed in the projecting portion <b>52</b><i>d </i>in the vicinity of a position close to a rear portion of the lower portion surface <b>52</b><i>f </i>thereof.

On a rear portion of the outer cowl <b>52</b>, a side cowl <b>61</b> of a rear cowl <b>60</b> having a pair of left and right symmetrical saddle bags <b>61</b><i>a </i>and a rear fender <b>61</b><i>b </i>is continuously mounted. A rear combination lamp <b>40</b> is mounted on a upper portion of a rear end of the rear cowl <b>60</b>.

The inner cowl <b>70</b> includes left and right inner cowls <b>72</b>, <b>72</b>. The left and right inner cowl <b>72</b>, <b>72</b> are integrally formed in the inside of the left and right outer cowls <b>52</b>, <b>52</b> by way of a hollow portion thus performing a function of enhancing the rigidity of the whole front cowl <b>50</b> and providing a reduction in the weight of the whole front cowl <b>50</b>. Since the left and right inner cowls <b>72</b>, <b>72</b> are formed to be symmetric in a left and right direction, only the left inner cowl <b>72</b> is explained here.

The inner cowl <b>72</b> includes a shell portion <b>72</b><i>a </i>which is not exposed to the outside and a radiator cover <b>71</b>. The shell portion <b>72</b><i>a </i>is arranged at an upper portion of the inner cowl <b>72</b> and is fixed to the frame side using a bolt. The radiator cover <b>71</b> which is arranged at a lower portion of the inner cowl <b>72</b> is fixed to the down tube <b>25</b> using a bolt. The radiator cover <b>71</b> is formed in a shape which allows the radiator cover <b>71</b> to cover from a side surface to a lower end portion of the radiator <b>23</b>.

Further, a bulging portion <b>71</b><i>a </i>is formed on the radiator cover <b>71</b>. The bulging portion <b>71</b><i>a </i>includes a lower end portion which projects toward a lower portion of the left outer cowl <b>52</b> of the radiator cover <b>71</b>, bulges in a droplet shape extending from a front portion to a rear portion, and is formed in an oblique rearward and upward direction as viewed in a vehicle side view. Further, an opening portion <b>71</b><i>b </i>is formed in a rear portion of the radiator cover <b>71</b>.

The bulging portion <b>71</b><i>a </i>is arranged on a lower end portion of the outer cowl <b>52</b> which is positioned in the vicinity of a rear portion of the front wheel <b>15</b> and projects downwardly. The bulging portion <b>71</b><i>a </i>bulges from a front portion to a rear portion and is formed in an oblique rearward and upward direction as viewed in a vehicle side view.

As shown in <figref idref="DRAWINGS">FIG. 3</figref>, with respect to the positional relationship between the bulging portion <b>71</b><i>a </i>of the radiator cover <b>71</b> and the projecting portion <b>52</b><i>d </i>of the outer cowl <b>52</b>, the projecting portion <b>52</b><i>d </i>is arranged behind the bulging portion <b>71</b><i>a</i>. The projecting portion <b>52</b><i>d </i>bulges more toward the outside of the vehicle body as compared to the bulging portion <b>71</b><i>a</i>. The projecting portion <b>52</b><i>d </i>is positioned above the bulging portion <b>71</b><i>a. </i>

As shown in <figref idref="DRAWINGS">FIG. 4</figref>, the bulging portion <b>71</b><i>a </i>of the radiator cover <b>71</b> receives and deflects the air A which flows rearwardly toward the front wheel <b>15</b> during operation of the vehicle. Thus, the deflected air A performs the function of applying a down force which pushes a vehicle body downwardly toward the front wheel <b>15</b>.

The opening portion <b>71</b><i>b </i>is formed in a rear portion of the radiator cover <b>71</b> in the vicinity of the bulging portion. Thus, by making use of a negative pressure which is generated by the air which is deflected as the air passes the bulging portion <b>71</b><i>a </i>of the radiator cover <b>71</b>, it is possible to make the air easily pass through the radiator <b>23</b>.

Accordingly, as indicated by a broken line shown in <figref idref="DRAWINGS">FIG. 4</figref>, since the projecting portion <b>52</b><i>d </i>can smoothly make use of a air B which is deflected toward the side of the vehicle body by the bulging portion <b>71</b><i>a </i>and is directed toward the rear portion of the vehicle body in the vicinity of the projecting portion <b>52</b><i>d </i>and, at the same time, the portion of the air B which is deflected toward the upper portion of the vehicle body by the bulging portion <b>71</b><i>a </i>is received by the lower portion surface <b>52</b><i>f </i>and is changed downwardly, the projecting portion <b>52</b><i>d </i>can reduce a portion of the air which is directed to a rider. The lower surface <b>52</b><i>f </i>of the projecting portion <b>52</b><i>d </i>extends rearwardly and downwardly and, at the same time, an air outlet <b>52</b><i>g </i>is arranged in the vicinity of the rear portion of the lower portion surface <b>52</b><i>f</i>. Thus, it is possible to allow the air which passes along the inner surface of the outer cowl <b>52</b> and air that is warmed around the engine to easily pass rearwardly through the air outlet <b>52</b><i>g. </i>

As shown in <figref idref="DRAWINGS">FIG. 5</figref>, the radiator <b>23</b> is arranged in a forwardly inclined manner by the radiator cover <b>71</b>. The radiator <b>23</b> is of a lateral-flow type in which a coolant which is introduced to a right side tank <b>23</b><i>a </i>of the radiator <b>23</b> flows into a left side tank <b>23</b><i>b </i>of the radiator <b>23</b> so as to cool the coolant. On a rear portion of the radiator <b>23</b>, a fan <b>41</b>, a blower motor <b>42</b>, a fan shroud <b>43</b> and a thermo switch <b>44</b> are mounted. The radiator <b>23</b> can enhance the engine cooling performance such that when a temperature of the coolant which flows in the inside of the radiator <b>23</b> exceeds a preset value, the thermo switch <b>44</b> is turned on. Thus, the blower motor <b>42</b> starts to rotate the fan <b>41</b>.

As shown in <figref idref="DRAWINGS">FIG. 6</figref>, the outer cowl <b>52</b> includes a stay <b>52</b><i>h </i>which extends in the inside of the middle-cowl notch <b>52</b><i>c </i>and a main-frame-fixing bolt hole <b>52</b><i>i </i>is formed in the stay <b>52</b><i>h</i>. Further, the outer cowl <b>52</b> includes a flange <b>52</b><i>j </i>on a lower end portion thereof and a main-frame-fixing bolt hole <b>52</b><i>k </i>is formed in the flange <b>52</b><i>j</i>. Further, the outer cowl <b>52</b> includes a flange <b>52</b><i>m </i>in the inside of the side blinker notch <b>52</b><i>b </i>formed in the front end portion of the outer cowl <b>52</b> and a front-bracket-fixing bolt hole <b>52</b><i>n </i>is formed in the flange <b>52</b><i>m. </i>

As shown in <figref idref="DRAWINGS">FIG. 7</figref>, a head-pipe-fixing bolt hole <b>72</b><i>b </i>and a main-frame-fixing bolt hole <b>72</b><i>c </i>are in a shell portion <b>72</b><i>a </i>of the inner cowl <b>72</b>, while a down-tube-fixing bolt hole <b>71</b><i>c </i>is also formed in a rear portion of the bulging portion <b>71</b><i>a </i>of the radiator cover <b>71</b>.

The bulging portion <b>71</b><i>a </i>is formed upwardly from a front portion to a rear portion of the radiator <b>23</b> and is brought into contact with an edge portion of the radiator <b>23</b>. Thus, the radiator <b>23</b> can efficiently introduce air which exists in a wide range in front of the radiator <b>23</b> compared to a radiator having no bulging portion <b>71</b><i>a. </i>

In the cowl structure of the vehicle <b>10</b> explained above, the bulging portion <b>71</b><i>a </i>which is formed in a direction to be oblique rearwardly and upwardly in a side view of the vehicle is, in the vicinity of the head pipe <b>12</b> and the front fork <b>13</b>, mounted on the lower end portion of the radiator cover <b>71</b> which covers from the side surface to the lower end of the radiator <b>23</b> arranged in front of both cylinder heads <b>17</b><i>a</i>, <b>17</b><i>b </i>of the engine <b>17</b>. Accordingly, it is possible to easily apply the down force which pushes the vehicle body in the downward direction to the front wheel <b>15</b>. Further, the bulging portion <b>71</b><i>a </i>which applies the down force to the front wheel <b>15</b> is mounted on the lower end portion of the radiator cover <b>71</b>. Thus, a longitudinal length of the vehicle can be shortened and the weight of the vehicle can be reduced. Further, the appearance of the vehicle can be enhanced.

In addition, in the above-mentioned cowl structure of the vehicle <b>10</b>, the projecting portions <b>52</b><i>d </i>of the left and right outer cowls <b>52</b>, <b>52</b> bulge to the outside of the vehicle body than the bulging portions <b>71</b><i>a </i>behind the radiator <b>23</b>. Thus, it is possible to enhance the aerodynamic characteristic by smoothly making use of the air which is deflected toward the side of the vehicle body by the bulging portions <b>71</b><i>a </i>and is directed toward the rear portion of the vehicle body in the vicinity of the bulging portions <b>71</b><i>a. </i>

Further, in the above-mentioned cowl structure of the vehicle <b>10</b>, the projecting portions <b>52</b><i>d </i>of the left and right outer cowls <b>52</b>, <b>52</b> are positioned above the bulging portions <b>71</b><i>a</i>. Thus, portions of the air which are deflected toward the upper portion of the vehicle body by the bulging portions <b>71</b><i>a </i>are received by the lower surfaces <b>52</b><i>f </i>of the projecting portions <b>52</b><i>d </i>so as to change the directions of the flow of the portions of the air downwardly whereby, it is possible to reduce an amount of the air on a rider (a driver) during operation of the vehicle.

In addition, in the above-mentioned cowl structure of the vehicle <b>10</b>, since the radiator cover <b>71</b> forms the opening portion <b>71</b><i>b </i>which opens toward the rear portion of the vehicle body, due to a negative pressure which is generated by the air which is deflected as the air passes the bulging portions <b>71</b><i>a </i>of the radiator cover <b>71</b> during the operation of the vehicle, the air can easily pass through the radiator <b>23</b>. Thus, it is possible to enhance a cooling efficiency of the radiator <b>23</b>.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.